Ultrasound, especially high-intensity focused ultrasound has been widely used in medical industry for diagnosis and treatment on a patient. A high-intensity focused ultrasound therapy is to focus the ultrasound on the diseased part, on which high-intensity and continuous ultrasonic energy is formed and thereby instantaneous thermal effect (60° C.˜100° C.), cavitation effect, mechanical effect and acoustic chemical effect are produced to destroy the cell membrane and nuclear membrane and coagulate the protein. Therefore, it can selectively cause a coagulative necrosis of the diseased tissue and accordingly deprives the diseased part of capability of proliferation, infiltration and metastasis. Furthermore, the high-intensity focused ultrasound therapy is not only used in tumor resection but also in treatment of other diseases, and it has been approved in clinical uses.
U.S. Pat. Nos. 5,882,302, 5,993,389 and 6,083,159 provide an ultrasound apparatus for surgery in the internal hemostasis by using a high-intensity focused ultrasound. U.S. Pat. Nos. 6,007,499 and 6,432,067 also provide a surgical ultrasound apparatus using a high-intensity focused ultrasound to form narcotic tissue regions before a surgery so as to avoid the bleeding of vasalium when performing surgery. The ultrasound transducer of this apparatus generates the focused ultrasound and emits continuously to a certain point of the diseased part. The treatment depth of the focal point can be varied by changing the positions of the ultrasound transducer.
The ultrasound apparatuses disclosed by the above-mentioned US patents can, to some extent, provide a hemostasis in the resection of tissue having a highly vascularized constitution, but there are some limits on the use of these apparatuses. Firstly, the operator needs to continuously move the large-sized ultrasound transducer by hand in the same angle according to different surgical incisions, so the operation procedure is very complex and also it is liable to cause mishandlings. Secondly, when the tissue to be treated is soft and incompact, the pressure generated by the apparatuses as mentioned above on the target tissue is not enough, so it is impossible to control the target tissue effectively, and if the target tissue can not be controlled, the ultrasonic energy can not arrive at the target tissue and the expected hemostasis can not be achieved. Thirdly, because the ultrasound apparatuses mentioned above can form only one focal point within the diseased part and usually the ultrasonic energy is attenuated on the acoustic path, it takes a lot of time to cause a coagulative necrosis of the relatively thick tissue (for example, the liver and spleen) during treatment and accordingly the cost is increased.